In order to improve the physical and/or optical properties of an ophthalmic lens, it is known to cover its main faces in one or more treatment layers presenting desired optical or physical properties, on one or both faces of the lens. Usually, the lens is dipped in a bath or a coating is applied in liquid form by centrifuging, or indeed by vacuum deposition of mineral or organic layers.
Recently, proposals have been made to use a solid coating in the form of a film that is initially carried by a support, which coating is transferred onto the corresponding face of the lens by adhesive bonding. A difficulty then consists in applying the coating carried by its support against the corresponding face of the lens in such a manner firstly as to ensure that no bubbles of air are held captive between the lens and the coating while it is being applied, and secondly as to spread the adhesive over the entire surface of the lens in order to distribute it in substantially uniform manner without any zones having too little or too much adhesive. It is also appropriate to obtain a thickness of adhesive that is well adapted to holding the coating well on the lens and to preserving the optical properties of the lens.
In an embodiment shown in its FIGS. 3A and 3B, document WO 03/004255 proposes a device for applying a coating film that is carried by a support onto a face of an ophthalmic lens. The device has a seat for receiving the lens and means for inflating a membrane. The support is put into place with its coating film on the face of the lens, with an interface that is disposed between the coating film and the lens. Thereafter the membrane is inflated towards the lens in order to press the coating film against the lens.
Nevertheless, it is found that after a certain number of membrane inflation cycles, the elastic deformation properties of the membrane deteriorate. In addition, while the membrane is being applied against the coating film support, in order to spread the adhesive between the coating film and the lens, the adhesive that is expelled from the sides of the lens can adhere to the membrane, and that is harmful since the membrane then becomes clogged and its elastic deformation properties are modified.
As a result, the membrane runs the risk of no longer deforming as desired and the coating runs the risk of no longer being applied uniformly against the lens without any bubbles of air.